electric power exchanges: a review - iit kanpur · electric power exchanges: a review yogesh k....

Electric Power Exchanges: A ReviewYogesh K. Bichpuriya

Department of Electrical EngineeringIndian Institute of Technology Bombay

Mumbai, India 400076Email: [email protected]

S. A. SomanDepartment of Electrical Engineering

Indian Institute of Technology BombayMumbai, India 400076

Email: [email protected]

Abstract—In this paper, an overview of electric power ex-changes is discussed. Trading mechanism, bid types and executionconditions are explained in brief. Features of various powerexchanges world wide are summarized.

Index Terms—Bid types, international experience, tradingmechanism.

I. INTRODUCTION

Electricity trading through Power Exchanges (PX) is hith-erto introduced in many electricity markets. In India, twopower exchanges viz., Indian Energy Exchange (IEX) andPower Exchange of India Ltd. (PXIL) are functioning withguidance from Central Electricity Regulatory Commission(CERC). Exchanges in India have only two years of experienceand are continuously evolving. Evolution of power exchangedepends on the experiences and lessons from internationalpower exchanges. Nord Pool power exchange (Elspot) is beingconsidered as a standard exchange design. Design and imple-mentation issues of a power exchange or power market, ingeneral, depend on the market supplies and demands, liquidity,economy etc. Philosophy of exchange design may vary fromcountry to country or exchange to exchange (working in thesame country). In India, electricity market is supply deficit(in some regions) and has a mix of different generationtechnologies. PX is a trading center where utilities, powermarketers, and other electricity suppliers submit price andquantity bids to sell energy or services, and potential customerssubmit offers to purchase energy or services. Key points of apower exchange include:• facility for trading of electricity• foster the development of competition• transparency• liquidityAccording to the section 66(178) of the Indian Electricity

Act 2003 [1], development of a market for electricity isresponsibility of the regulators. In light of the same, CERCtook an initiative to develop a common platform for electricitytrading with its staff paper on July 20, 2006 [2]. The CERCalso suggested function diagram of a power exchange. Indianelectric sector is in the process of becoming an industry byopening energy markets, unbundling the electricity servicesand opening access to electrical networks. It is deemed thatmore options and freedom to market participants may stimu-late competition in power trading, in order to achieve lower

power prices, improvement of system efficiency and incentivesto innovation.

It is a well known fact that electricity is a commodity muchdifferent than other commodities for trading. The distinguish-able features of electric power make the trading of electricitymore complex and need to consider technical, economical andregulatory aspects while designing the market.

The idea of trading through an exchange enables the tradersto discover the best price in the market and to find theoptimum buyer or seller for trade. Power exchange introducestransparency in the market clearing and reduces counter-partycredit risk. Exchange manages trades, clears market and settlesfinancial transactions. In the electricity market, the exchangeis synchronized with Transmission System Operator (TSO) toget technical clearance for transacting power over the grid.

Trading should be done in an efficient manner to providequality and affordable power to end users. Power exchangeformation could prove to be a mile stone in the abovementioned purpose. Power Exchange (PX) directly operateswholesale energy markets, such as day-ahead and hour-aheadmarkets, while the real-time market for energy balancing andthe market for the ancillary services may be operated directlyby the TSO or by PX on behalf of TSO and under specifictechnical requirements. The TSO controls and operates thetransmission grid and facilitates transactions and transmissionavoiding influence on the generation schedules created by thePX. Success factor of a PX can be measured with the followinginputs:• Number of participants in PX• Liquidity in the market• Market growth in terms of traded volume• Competitiveness of fee structureFor PX, the day-ahead energy market is based on a single or

double-side auction scheme. Single side auction allows eitherbuyers or sellers to submit their bids or offers respectively.In double sided auction scheme, both power suppliers andconsumers are allowed to submit volume-price offers and bidsrespectively. Auction process can be open or closed (sealed).In open auction participants repeatedly bid and know about theprevious bids. In close or sealed auction, bids or offers are notopened to the market participants. In most of the PX, doublesided sealed auction scheme is implemented. Participation inelectricity trading through exchange can be mandatory or vol-untary. Mandatory participation, though, maximizes the traded

16th NATIONAL POWER SYSTEMS CONFERENCE, 15th-17th DECEMBER, 2010 115

Department of Electrical Engineering, Univ. College of Engg., Osmania University, Hyderabad, A.P, INDIA.

volume and better price discovery in the market, it restricts theparticipants for arranging bilateral contracts. Electricity flowson a transportation network and physical delivery of tradesmay cause congestion in the network. Issue of congestionshould be handled in the market clearing mechanism. Con-gestion management techniques differ in implicit and explicitauctions. Some PX use market splitting method in case ofnetwork congestion [3]. The issue of congestion managementis not discussed in this paper.

Most of the exchanges provide hourly and block bidproducts. Some new bid structures are also proposed in [4]considering generators’ start up and shut down cost. In [5],authors present a new concept of coupling of emission tradingwith the MW trading on the exchange.

In the next section, the components of electricity tradingthrough an exchange are discussed. Section III of the paperdiscusses the design issues of a power exchange in terms ofbid types, execution and validity conditions and bid matching.International experiences on power exchanges are investigatedin Section IV. Section V concludes the paper.

II. ELECTRICITY TRADING

In electricity market, power can be traded either bilaterallyor via exchange. Bilateral contracts are negotiated betweentwo parties, one being buyer and other the seller. The contractprice information is, therefore, limited to the parties involved.New traders in the market may face difficulty in making agood deal or be unable to explore the market. In this typeof contract, traders also have credit risk in case of default bycounter party.

On the other hand, exchange trading is a more sophisticatedway to make deals and explore the market. Traders can quotetheir offers and bids a day ahead of physical delivery. Theexchange aggregates the offers and bids separately and clearsthe market on the basis of supply-demand equilibrium [6].In Fig. 1, the intersection point of supply and demand curvedetermines the MCP and MCV. This point is called equilibriumpoint. At the equilibrium point, the offer price equals the bidprice for the same volume of electricity. For a bid to be cleared,the bid price should be higher than or equal to the MCP andfor an offer to be cleared, the offer price should be lowerthan or equal to the MCP. The orders can be executed fullyor partially as per the trader’s instructions.

Exchange, in this way, discovers price in the market andarranges good deals for its members. Exchanges also eliminatethe counter party credit risk by having the bank guarantee of itsmembers. All financial transactions and settlements are donevia exchange and associated clearing bank(s).

Primary objective of a market clearing exchange is to max-imize the social welfare which is the sum of the consumers’surplus and producers’ surplus.

1) Consumers’ Surplus: Consumers’ surplus is product ofquantity and the difference between consumers’ bid price andmarket clearing price. This is a surplus to the consumers inthe sense that they get the quantity at lesser price than theirbids.

P(Rs.)

MCP

MCQQ(MW)

Demand Curve

Supply Curve

Qd1

Qd2

Qd3

Qs1

Qs2

Qs3

Qs4

SurplusConsumers’

SurplusSuppliers’

Qd4

Market Equilibrium(MCQ, MCP)

Fig. 1. Market Equilibrium and Social Welfare

2) Producers’ Surplus: Producers’ surplus is the productof quantity and the difference between the market price andthe offer price. In a fully competitive market, the offer pricesubmitted by a supplier is equal to the marginal cost ofproduction. In monopoly or oligopoly market, offer price canbe higher than the marginal cost of production.

3) Social Welfare: The sum of the consumers’ surplus andthe producers’ surplus is called total or social welfare (Fig.1).Maximization of social welfare in an uncongested marketresults in the equilibrium point.

III. DESIGN ISSUES OF POWER EXCHANGE

A. Bid Types

Generally, exchanges provide at least a day-ahead market,where the bids are submitted and the market is cleared onthe day before the actual dispatch. The day to be scheduledis divided into n periods of m minutes each. Each biddingfirm makes a price for for every generation unit for the wholeday. In the day-ahead market either hourly contracts (forthe 24 hours of the calendar day) or block contracts (i.e. anumber of successive hours) are common. Whereas the formerallows the market participants to balance their portfolio ofphysical contracts, the latter allows them to bring completepower plant capacities into the auction process. Block contractbidding may either be organized for a certain number ofstandardized blocks, or for flexible blocks. Along with day-ahead market, many exchanges also offer intra-day market andother customized products like weekend peak or weekend baseload. Exchanges across the world have a wide range of suchproducts due to market responses and innovations. We discussonly hourly and block products.

1) Hourly Products: Hourly bids/offers are the simplestproduct in most of the power exchanges except UKPX. In UK,a simple product of half hour is provided [7]. Genesis of thehourly product could be on the basis of demand supply balanceat each point of time. For practical purposes, the hourly auctionis a good choice for the TSO. Auction having only hourlyproduct is easy to implement and involves less computationaleffort.

In a double side auction with only simple hourly bids,hourly auction problem can be formulated as an optimization



problem of maximizing social welfare subject to the constraintthat total supply at the optimal point is equal to the totaldemand at that point. Linear programming problem for 24decoupled hourly auction can be represented as

max

∑

j

Phdj × Qh

dj −∑

i

Phsi × Qh

si

subject to:

0 ≤ Qhdj ≤ Qhmax

dj (1)

0 ≤ Qhsj ≤ Qhmax

sj (2)∑

j

Qhdj =

∑

i

Qhsi (3)

h ∈ {1, 2, · · · , 24}

Where Phdj and Qh

dj are bid price and bid quantity submittedby customer j in hth hour and Ph

si respectively and Qhsi are

offer price and offer quantity submitted by supplier i in hth

hour respectively. Lagrangian multiplier associated with theconstraint (3) gives the market clearing price.

Note that the transportation network is assumed to beuncongested and lossless in the above formulation.

2) Block Products: In electricity market the supplier, hav-ing a generator with high start up or shut down cost, mayfeel the hourly products economically inefficient. Suppose,a supplier submits offers for hourly products for, say, 10consecutive hours and cleared only in alternate hours. In otherwords, the supplier has to run his generator for hour 1, thenshut off for hour 2 and then again run for hour 3 and soon. Thermal generators have high start up and shut down costand to avoid this type of situation, they may not opt for hourlyproducts. It is therefore economically efficient to submit offersin blocks of 4 hours each. So, if he gets into the market for firstblock and goes out of the market for next block or vice versa,he can save the start up and shut down cost as compared tothe hourly products. This may also help him to submit offersat a lower price. The concept of block offers is more usefulfor suppliers.

The block products can be flexible (ie no. of hours in ablock may vary) or standardized. The flexible block productscan be customized by the traders as per their convenience andperception of the market. Standardized block products, on theother hand, are exchange specified blocks of hours and arebased on the load pattern of the market.

Remark 1: When block products are considered in the auc-tion, it becomes a combinatorial auction. Mixed Integer LinearProgramming (MILP) problem for combinatorial auction canbe formulated as.

max24∑

h=1

∑

j

Phdj × Qh

dj −∑

i

Phsi × Qh

si

−∑

k∈BPsk ×Qsk

subject to:

0 ≤ Qhdj ≤ Qhmax

dj (4)

0 ≤ Qhsj ≤ Qhmax

sj (5)

Qsk = xk.Qmaxsk xk ∈ [0, 1] (6)∑

j

Qhdj =

∑

i

Qhsi +

∑

k∈B(h)

Qsk (7)

B =⋃

B(h)

h ∈ {1, 2, · · · , 24}

Where B(h) is the set of block offer active in hth hour. Psk

and Qsk are block offer price and block volume respectively.xk is a binary variable and assigned a value 1 if the blockoffer is selected. It can be proved that the power exchangebid matching problem with block bids is an NP-complete i.e.intractable problem.

Remark 2: In the above mentioned MILP problem, hourlyor block offers can be rejected paradoxically. The term para-doxically used in the context that even PsR < MCP forhourly offers (where R is a set of rejected hourly offers)or PsBR < MCP for block offers (where BR is a set ofrejected block offers) and still these offers are rejected dueto inflexibility in the constraint (7). Some exchanges do notreject hourly offers (if the MCP criteria is met) but allowrejections of block offers. To model Paradoxically RejectedBlocks (PRB), few more constraints are to be added in theabove formulation [8].

B. Execution Conditions

PX may also facilitate traders with execution conditionspecifications i.e. an order (buy or sell) is cleared only accord-ing to the execution conditions. On the electronic exchanges,the execution conditions conveys the trader’s wish with theirorders as they would not be present at the time of executionof their orders. In general, the execution conditions can beapplied to both hourly and block bids. For some conditions,hourly or block bids should have flexible time blocks. Someof the popular execution conditions are listed here [9].

1) All-or-None: With this specification, if the order can beexecuted in total, then it executes. Otherwise it stays in theorder book until it can be executed in total. For example,a generator submits a 20 MW sell offer with the all-or-none conditions, then the exchange clearing mechanism canschedule the offer of full quantity any time before expiry of theoffer. If the offer is not executed in full in the entire validityperiod it will be removed from the order book.

2) Full-or-Partial: Orders can be partially matched withopposite orders for smaller quantities, in which case theunexecuted quantity remains in the order book. For example,



a generator submits a 20 MW sell offer with the full-or-partial conditions, then the exchange clearing mechanism canclear the offer partially (say 15 MW) in one time block andremaining (5 MW) in other block before expiry of the offer.

3) Fill-or-Kill: FOK orders are canceled if not immediatelyfilled for the total quantity at the specified price or better. Forexample, a generator submits a 20 MW sell offer with the fill-or-kill conditions, then the exchange clearing mechanism canschedule the offer of full quantity in the specified time blockonly. If the offer is not executed in full, it will be removedfrom the order book.

4) Fill-and-Kill: FAK order is immediately filled in wholeor in part at the specified price. Any remaining quantityis eliminated. For example, a generator submits a 20 MWsell offer with the fill-and-kill conditions, then the exchangeclearing mechanism can schedule the offer of full or partialquantity in the specified time block only. If the offer is notexecuted, it will be removed from the order book.

5) Minimum Income and Maximum Payment Condition:In this type of execution condition sellers specify minimumincome condition and buyers specify maximum payment con-dition with their orders. The minimum income condition refersto the equation of the number of consecutive hours, the volumeand the limiting price. A block bid can be matched in casethe limiting price is equal to, or lower than, the average pricethrough out the defined block of hours. A block bid must bematched for the entire volume specified and for all hours. Ifthis is not possible, the block bid is rejected.

C. Demand and Supply Curves

Clearing a single market involves setting the price andconsequently matching demand and supply at that price. Formatching offers and bids there are some matching rules fortotal surplus maximization.• Stepwise clearing• Piecewise linear clearingIn case of stepwise clearing, the results may not be unique

and there may be a qualified range of volume and price. Fourpossible cases of intersection of demand and supply curves instepwise clearing are shown in the Figs. 2-5. First two cases(Fig. 2,3) have unique equilibrium point. Fig.4 is a case ofvertical intersection of the two curves. The vertical intersectionof the curves provide flexibility in the market clearing price.Similarly, the horizontal case (Fig. 5) of intersection providesflexibility in the market clearing volume. To determine thesingle market clearing price and market clearing volume, thePX has to specify some additional rules. The stepwise clearingscheme is implemented in APX [10]. On the other handpiecewise linear clearing gives the single market equilibriumpoint (Fig.6). Some exchanges use linear interpolation insteadof simple aggregation to get piecewise linear curves. NordPool power exchange uses the linear interpolation techniquefor piecewise clearing [11].

In [12], the four intersection cases of stepwise clearing arediscussed and compared with piecewise clearing results. Itis also concluded in the paper that unlike stepwise clearing,

P(Rs.)

MCP

MCQQ(MW)

Demand Curve

Supply Curve

Fig. 2. Single equilibrium point case 1

P(Rs.)

Q(MW)

Demand Curve

MCP

MCQ

Supply Curve

Fig. 3. Single equilibrium point case 2

P(Rs.)

Q(MW)

Demand Curve

MCQ

Avg MCPMax MCP

Min MCP

Supply Curve

Fig. 4. Multiple MCP in case of Step-wise clearing

P(Rs.)

Q(MW)

Demand Curve

MCP

Max MCQMin MCQ

Supply Curve

Fig. 5. Multiple MCQ in case of Step-wise clearing

P(Rs.)

Q(MW)

Demand Curve

Supply Curve

MCP

MCQ

Fig. 6. Piecewise linear curve

piecewise clearing does not always maximize wealth forparticipants.



IV. INTERNATIONAL EXPERIENCE

This section briefly introduces features of power exchangesacross the world. Thirteen power exchanges are investigatedin this work but only seven exchanges are discussed herewith their important features. Other exchanges are not muchdifferent from market mechanism aspects. Table I and IIsummarize the types of markets and bids implemented inpower exchanges [7], [10], [11], [13], [14], [15], [16], [17],[18], [19], [20], [21], [22], [23], [24].

A. Nord Pool, Norway/Sweden/Finland

Nord Pool exchange is considered as a model PX in manyemerging PX designs [11], [14]. Nord Pool exchange has twosegments:

1) Elspot: This segment of market offers day ahead auctionfor individual hourly contracts and block bids. The block bidsare the standardized ones and typically divided into five blocksperiods: (BB 1-7), (BB 8-18), (BB 19-24), (BB 1-24) and (BB8-24).

Along with these products, Nord Pool also provides someinteresting mechanisms to the participants. These mechanismsare:• Linked Block Bids All block bids that are linked together

must be either only sales or purchase blocks, and alllinked block bids must be connected to one biddingportfolio in one bidding area.

• Flexible Hourly Bids The flexible hourly bid is a salesbid for a single hour with a fixed price and volume. Thehour is not specified, but instead the bid will be acceptedin the hour with the highest price in the calculation, giventhat the price is higher than the limit set in the bid.

• Conversion of Block Bids In this mechanism a notactivated block bid can be converted to regular hourlybids. This will help in case of under supply offers forhourly products. This is a non-mandatory option for thesuppliers.

2) Elbas: The Elbas market provides continuous powertrading 24 hours a day, 7 days a week covering individualhours, up to one hour prior to delivery. The traded productsare one-hour long power contracts. The time span between theday’s Elspot price-fixing and the actual delivery hour of theconcluded contracts is quite long (36 hours at the most). Asconsumption and production situations change, a market playermay find a need for trading during these 36 hours. The ElbasMarket enables continuous trading with contracts that lead tophysical delivery for the hours that have been traded on theElspot market and are more than one hour from delivery. TheElbas market is open around the clock every day of the year.

B. Amsterdam Power Exchange (APX), The Netherlands

The APX has day ahead spot market and also an adjustmentmarket, ie intra-day market [10]. Day ahead market enablesmarket participants to trade electricity for hours of a day oneday in advance. The participants are also allowed to trade forblocks of hours. The blocks offered in the PX are standardized

as well as flexible. The block bids are executed under twoconditions:

1) FOK2) Minimum income or Maximum payment condition

The adjustment market at the PX is to minimize the unex-pected imbalances. This segment of PX provides continuoustrading.

C. European Energy Exchange (EEX), Germany

The EEX offers day ahead market with individual hourcontracts and standardized blocks for auction [16]. The EEXalso enables market participants for continuous trading. Thereare several execution conditions selectable to specify the bids.Standardized block products offered in EEX are: (EEX NightHours 1-6), (EEX Morning Hours 7-10), (Business Hours 9-16), (EEX High Noon Hours 11-14), (EEX Afternoon Hours15-18), (EEX Rush-Hour Hours 17-20), (EEX Evening Hours19-24), (Base Load Hours 1-24), (Peak Load Hours 9-20),(Off-Peak Load Hours 1-8 and 21-24), (Off-Peak-1 Hours 1-8) and (Off-Peak-2 Hours 21-24).

D. Powernext, France

Powernext offers standard hourly products in day aheadmarket and price limited block orders that link a minimum offour hours of a day together [19]. The standard blocks offeredby Powernext are:• Three hours block bids (Block Bid 1-4), (BB 5-8), (BB

9-12), (BB 13-16), (BB 17-20) and (BB 21-24)• Other block bids (BB 9-20), (Bb 1-6), (BB 1-8) and

(BB 9-16)

E. Belgium Power Exchange(Belpex),Belgium

The Belpex market is subdivided into three segments [15].These segments are designed for hourly and block bidding oneday in advance and for continuous trading.• Belpex Day Ahead Market Segment (Belpex DAM)

provides standardized products (hourly instruments).Prices are determined via a double-sided blind auction.It also has Market Coupling Auction.

• Belpex Continuous Day Ahead Market Segment(Belpex CoDAM) provides standardized products (multihourly instruments) to sell and purchase electricity on acontinuous basis as from 2 trading days before deliveryup to 11:00 am of the day before the delivery.

• Belpex Continuous Intraday Market Segment (BelpexCIM) provides standardized products (hourly and multihourly instruments) to sell and purchase electricity on acontinuous basis, and this up to 5 minutes before delivery.

F. Indian Energy Exchange (IEX),India

IEX [17] is the first Indian power exchange established in2008. It has two sub-markets: Day Ahead Market (DAM)and Term Ahead Market (TAM). DAM offers 24 separatehourly products. Price discovery in DAM is through doubleside bidding and buyers and suppliers pay/receive uniformprice. TAM offers Intra-day, Day-ahead contingency, Daily



TABLE ITYPES OF MARKETS IN POWER EXCHANGES

Type of Market Power ExchangesDay Ahead Market APX Power, Belpex(DAM),

Brozen, EEX, JEPX, KPX,NordPool(Elspot), Polpx,PowerNext, PXIL and WESM

Intraday Market APX Power, Belpex(CIM), Brozen,EEX, NordPool and PowerNext

Other products(term ahead, daybase, day peak,etc.) market

APX Power, Belpex(CoDAM),EEX, PowerNext, PXIL

TABLE IITYPES OF BIDS IN POWER EXCHANGES

Type of Bids Time Limits PowerExchanges

Hourly Bids Specified timeblock

All PX

Flexible (Ts, Te) NordPool

Block BidsStandard blockbids

Belpex, Brozen,EEX, Powernext,PXIL

Flexible blockbids

PowerNext

Linked blockbids

NordPool

and Weekly contracts. Matching in Intra-day, Day-ahead andDaily contracts are based on continuous trading sessions whilematching in Weekly contracts is through uniform price auction.DAM and TAM operations are carried out in accordance withthe CERC guidelines.

G. Power Exchange India Limited (PXIL), India

PXIL [18] is the second Indian power exchange. It offersDay Ahead Market (DAM) and Term Ahead Market (TAM).DAM offers hourly and block bids. The execution criterion forblock bids is all-or-none. TAM offers Day-ahead Contingencyand Weekly contracts.

V. CONCLUSION

The paper provides overview of PX concepts and its imple-mentation world wide. Issues that need further investigationare congestion management, advanced bid structures, emissiontrading, etc.

REFERENCES

[1] The Indian electricity act 2003. [Online]. Available:http://www.cercind.gov.in

[2] “Staff paper on developing a common platform for electricity trading,”CERC, Jul. 2006.

[3] Y. Bichpuriya, S. A. Soman, and P. R. Apte, “Design and testing ofheuristic for market splitting in electric power exchange,” TENCON2009, IEEE Region 10 Conference, Jan. 2009.

[4] R. Gajbhiye and S. A. Soman, “New bid structures for power exchangewith modelling in ilp framework,” European Energy Market Conf. 2009,2009.

[5] ——, “Facilitating emission trade within power exchange: Developmentof conceptual platform,” European Energy Market Conf. 2010, 2010.

[6] R.S.Pindyck and D. L. Rubinfeld, Microeconomics. Delhi: PearsonEducation Asia, 2002.

[7] United Kingdom power exchange, UK. [Online]. Available:http://www.ukpx.com

[8] L.Meeus, K. Verhaegen, and R. Belmans, “Block order restrictions incombinatorial electric energy auctions,” European Journal on Opera-tional Research, vol. 196, no. 3, pp. 1202–1206, 2009.

[9] L. Harris, Trading and Exchanges: Market Microstructure for Praction-ers. Delhi: Oxford University Press, 2008.

[10] Amsterdam power exchange, Netherlands. [Online]. Available:http://www.apx.nl

[11] Nord pool. [Online]. Available: http://www.nordpoolspot.com/[12] L.Meeus, K. Purchala, and R. Belmans, “Implementation aspects of

power exchanges,” CIGRE, 2004.[13] R. Madlener and M. Kaufmann, “Power exchange spot market trading in

Europe: theoretical considerations and empirical evidence,” OSCOGEN,Mar. 2002.

[14] “Trade at the Nordic spot market:the world’s first international spotpower exchange,” Apr. 2004.

[15] Belgium power exchange, Belgium. [Online]. Available:http://www.belpex.be

[16] European energy exchange, Germany. [Online]. Available:http://www.eex.com/en

[17] Indian energy exchange, India. [Online]. Available:http://www.iexindia.com

[18] Power exchange India limited, India. [Online]. Available:http://www.powerexindia.com/

[19] Powernext, France. [Online]. Available: http://www.powernext.fr/[20] Polish power exchange,Polish. [Online]. Available: http://www.polpx.pl/[21] Korea power exchange, Korea. [Online]. Available:

http://www.kpx.or.kr/english[22] Japan energy power exchange, Japan. [Online]. Available:

http://www.jepx.org/English[23] Brozen, Slovenia. [Online]. Available: http://www.borzen.si/eng/[24] WESM, Philippines. [Online]. Available: http://www.wesm.ph/



electric power exchanges: a review - iit kanpur · electric power exchanges: a review yogesh k....

Documents